1. Field of the Invention
This invention relates to a recording material used for recording high energy rays.
2. Description of the Prior Art
As recording materials used for recording high energy rays such as a laser, there are known silver salt light-sensitive materials as well as recording materials having a recording layer composed of a substance which undergoes a thermal change such as melting or evaporation upon the application of heat energy or irradiation (e.g., see Applied Physics, 42, No. 11, pp. 1052-1066 (1973)). For recording on such recording materials, information is, in general, converted into electrical signals, and laser beams which are modulated corresponding to the signals are applied to the recording material to record the information thereon. This recording system has the advantages of rapid information processing and low cost of the light-sensitive materials used. Suitable recording materials used are, unlike silver salt light-sensitive materials, metals, dyes, plastics and the like which can be thermally recorded without requiring after-processing such as development. Moreover, these recording materials can immediately form an image (real time image formation) and are inexpensive. These recording materials are described, e.g., in M. L. Levene et al., Record of 11th Symposium on Electron, Ion and Laser Beam Technology, (1969), Electronics, p. 50 (Mar. 18, 1968), D. Maydan, The Bell System Technical Journal, 50, p. 1761 (1971), C. O. Carlson, Science, 154, p. 1550 (1966), etc.
However, recording on these recording materials requires a light source of high output because of their low recording sensitivity on high-speed scanning, and the devices for recording are expensive and of large size. Therefore, it has been desired to increase the recording sensitivity thereof on high-speed scanning. One method of increasing recording sensitivity is to use a recording material having a three-layer construction comprising selenium, bismuth and germanium, as described in Japanese Patent Publication No. 40,479/71. However, the use of selenium, bismuth and the like involves the danger of environmental pollution, and, moreover, there are many problems with the quality of the recorded image.